[Swagger tooling] Improve test coverage( 80%)

[akning-ms]

Add more test case to improve test coverage for different tools

[akning-ms]

avocado: 100% azure-openapi-validator: 95.5% for ts, 84.6% for dotnet oav: liveValidator: 89%, modelValidator: 82%, semanticValidator: 92%, trafficValidator: 13%, exampleGenerator: 85%, apiTests: 19% openapi-diff: 85% for dotnet, 48% for ts openapi-enumerator: 58.18% for statements openapi-github:78% openapi-LiveValidation:61.45% for backend. 26.51% for frontend. openapi-portal: 72.3% for frontend and backend openapi-telemetry: 100% openapi-tools: 70.5% for unit test, 100% for Api integration tests openapi-tools-common: 75% openapi-alps:

• openapi-kebab  47% + integration tests
• publish-pipeline-result              82%  
• swagger-validation-common   80%